1. Field of the Invention
This invention relates in general to the field of mining and, in particular, to a novel method to relocate and position bulk solids handling machinery used in surface mining activities.
2. Description of Prior Art
Bulk solids handling machinery such as slurry sluicing systems, conveyor belt systems, drag conveyor systems, crushers, grinders, screens, centrifuges, cyclones and other equipment and systems, are used to transport or treat material such as ore, farm products, wood chips, and other bulk solid materials, These systems may be used to move these bulk materials from stockpiles, settling ponds, spill collection areas, mining or agricultural operations and other situations.
In many cases, operation of these systems requires the systems to be periodically relocated. Material close to and within reach of the system is gathered and transported by the system. Continued operation causes the distance between the bulk solids and the handling system to increase until continued operation is either impossible or unacceptably inefficient. At that time, operation of the handling system is suspended and the system is relocated closer to the bulk solids. Multiple repetitions of this cycle advance the system through the material,
Relocation of the bulk solids handling machinery is frequently accomplished by mounting the equipment on "crawlers" comprised of an endless chain of bearing pads that are driven by motors to loop around a pair of sprockets. A reader familiar in the art of bulk solids handling machinery will recognize this system as that of tracked equipment such as bulldozers and backhoes.
While the crawler system described above provides great operational flexibility, it also suffers from two disadvantages. Firstly, the crawler system is a complex machinery unit with multiple moving parts that are expensive to manufacture and to maintain. Secondly, the crawler system has limited bearing surface over which to distribute the weight of the crawler and bulk handling equipment. This means that crawler systems cannot economically operate on surfaces with low bearing strength such as that found in wet or clayey soils. While the width and length of the crawlers may be increased to provide greater bearing surface, the cost of manufacture and operation increases accordingly. Thus, it is seen that crawler systems are limited to working on surfaces with good bearing strength and where the need for a highly mobile operation overcomes the disadvantage of high costs.
Relocation of the bulk solids handling machinery is frequently accomplished by mounting the equipment on wheels. This method is favored in situations where the equipment is frequently relocated over long distances, as is the case with haulage trucks or portable crushers and screens. Wheel mounted systems provide very small bearing surface over which to distribute the equipment weight and are therefore limited to working on surfaces with very good bearing strength.
Relocation of the bulk solids handling machinery is frequently accomplished by mounting the equipment on skids. These units may be economically manufactured and maintained to provide bearing surfaces large enough to support very large equipment units on very soft surfaces with very low bearing strength. However, these units have no self-propulsion mechanism and must be drug or pushed into position by wheeled or tracked equipment described previously. Thus, this method of equipment relocation is limited to situations where relocation is infrequent.
A specialized self propelled equipment skid is taught by the prior art. These units are comprised of two piece skids connected by hydraulic cylinders that alternately extend to thrust the leading skid ahead and retract to pull the trailing skid back into position behind the leading skid. These units can operate only in confined spaces, such as trenches or in underground mines. Hydraulic cylinders must be extended between the side walls of the trench or between the mine roof and mine floor to anchor the trailing skid while the leading skid is advanced and similarly to anchor the leading skid while the trailing skid is advanced.
None of the existing means for relocating bulk solids handling equipment address the situation where the equipment is required to frequently or continuously travel across surfaces with very low bearing support unless the equipment is operating within a confined space such as a trench or underground mine.